1. Field of the Invention
The present invention relates to a medial apparatus and, more particularly, to a medical apparatus capable of performing observation based on fluorescence emitted from a fluorescent drug.
2. Description of the Related Art
In recent years, a cancer diagnosis technique employing a molecular target drug has started to attract attention. Specifically, for example, a method of, after administering a fluorescent drug (a fluorescent probe) targeting living body protein, which specifically develops in a cancer cell, to a living body, determining presence or absence of cancer based on fluorescence emitted in a target region of the living body has been studied in recent years. Such a method is useful in early detection of cancer in a digestive tract field.
As an application of the method, a method of, after administering plural kinds of fluorescent drugs having different fluorescence wavelengths to a living body, complexly observing, based on plural fluorescences emitted in a target region of the living body, development states of plural kinds of living body protein corresponding to the plural kinds of fluorescent drugs is being proposed. Such a method is considered to be useful in, for example, estimation of a stage of cancer, prediction of an infiltration risk of cancer, and prediction of a metastasis risk of cancer.
For example, Japanese Patent Application Laid-Open Publication No. 2006-61683 discloses an endoscope apparatus including a laser beam source that generates excitation light, an endoscope scope including an irradiating section of the excitation light at a distal end portion thereof, an intensifier incorporating a charge coupled device (hereinafter abbreviated as CCD that detects fluorescence generated in a subject by the excitation light, fluorescent image generating means for generating a fluorescent image signal based on a fluorescent signal from the intensifier incorporating CCD, distance measuring means for generating a distance signal corresponding to a distance between the irradiating section and the subject, fluorescence amount calculating means for correcting the fluorescent signal with the distance signal and calculating a fluorescence amount not affected by fluctuation in the distance. In the endoscope apparatus, the fluorescence amount calculating means includes time-after-drug-administration correcting means for correcting the fluorescent signal or the fluorescent image signal based on an elapsed time after the fluorescent drug is administered.
The configuration disclosed in Japanese Patent Application Laid-Open Publication No. 2006-61683 makes it possible to correct, even before the influence of the administered fluorescent drug spreads all over the subject, a fluorescent image to a state after the influence of the fluorescent drug spreads all over the subject.